The present invention relates to an apparatus and method for providing a broadcast digital radio service in which the user is afforded various interactive features.
Various digital communication protocols have been developed for communicating audio and other data in a packetized data stream. For example, digital audio streams which conform to the ISO/IEC International Standard 13818-1, Musicam, and Dolby AC-2 and AC-3 formats are known. ISO/IEC 13818-1, also published as ITU-T Recommendation H.222.0, is compatible with the MPEG-2 video standard described in ITU-T Rec. H.262, or ISO/IEC 13818-2 and 13818-3. These schemes can provide for the communication of compressed audio data over various broadcast channels, including satellite, cable television, or terrestrial networks, for example. Other digital formats are known for the communication of video and other types of data.
However, such schemes are not designed to enable the user to interact with the data. For example, in an audio context it has not been possible to manipulate received audio data to provide features which are normally associated with a compact disc (CD) player. Such features include skipping a track in forward or reverse, pausing the audio output, fast forward or reverse, or repeating an audio selection from the beginning of a track. Similarly, with analog radio broadcasts, the user has no control over the received data other than changing the channel. Thus, the user has been forced to obtain pre-recorded media such as compact discs or magnetic tape in order to enjoy such features.
Accordingly, it would be desirable to provide a digital radio broadcast system which affords the user various interactive features. The system should take advantage of digital technology such as packet delivery of multiple concurrent data streams, and digital storage and control.
It would also be desirable to provide an audio receiver/player which gives the user information about the selection currently playing, such as a textual display which provides the name, performer, album, lyrics or time/duration of the selection, or even a verbal (e.g., vocal) description.
The system should be configurable in various tiers, for example, as an access-controlled, commercial-free service, or as a free service which includes commercials.
The system should be compatible with audio data as well as video and multimedia data.
The system should be compatible with existing and proposed governmental regulations and commercial standards regarding terrestrial channel allocations.
The present invention provides a system having the above and other advantages.
In accordance with the present invention, a digital radio broadcast system provides various interactive features, including skip forward and skip backward. In one embodiment, data is transmitted at a faster than real time rate and accumulated in a buffer at a receiver. The data rate may reduced, at least temporarily, to the real-time rate. The user can play a current track or skip to subsequent or earlier tracks.
In another embodiment, two or more channels of programming are communicated such that a user can move directly from a current track to the beginning of a track on another channel. The channels may be transmitted at real time or faster than real time. In another embodiment, tiers of service levels are provided so that a paying subscriber can bypass some or all of the commercial messages, while non-paying users may not bypass the commercials. Replacement programming for use in overriding commercials (e.g., for paying customers) may be transmitted in one or more portions of available bandwidth. At a receiver, control data may provide identification of a track, such as artist, song title, or the like.
In particular, a method for broadcasting digital programming services includes the steps of packetizing a plurality of program segments for transport in at least one data stream, transmitting the packetized program segments at an overall data rate which is greater than a play rate of the program services, temporarily storing at least a portion of the program segments in a buffer, and deleting at least one program segment in the buffer when a buffer fullness level is reached.
The packetized program segments may be transmitted in only one data stream at a rate which is greater than a play rate of the programming services.
Data may also be transmitted which designates access points for the program segments to allow a user to skip forward or backward to a program segment which is stored in the buffer while playing current program segments.
The buffer contents must be managed to avoid an overflow. This can be achieved by deleting the oldest program segment which is stored in the buffer when the buffer fullness level is reached.
Additionally, control data may be transmitted with the program segments to provide information regarding the contents of the program segments such as song title, artist, lyrics, etc.
The scheme is particularly suitable for use with audio data, although the inventive concept can be extended to video and multimedia data. The term xe2x80x9cmultimediaxe2x80x9d is used herein to indicate audio and/or video data. Currently, the required memory size for video and multimedia is believed to be prohibitive, but this is expected to change as memory costs continue to decline and improvements in data compression are achieved.
For marketing purposes, it is desirable to provide a plurality of service tiers, e.g., a free or basic service level, and one or more premium (subscriber) levels. For example, a free service level would have a number of commercials for each hour of music or other programming, while a mid level premium service has fewer commercials, and a high level premium service has no commercials. This can be achieved by providing only the paying customers with data which indicates access points for the program segments. The access points allow a user to skip forward or backward to a program segment which is stored in the buffer after the user has begun to play a current program segment. In this manner, some users can skip over at least some of the commercial segments, while others cannot skip over the commercial segments. Moreover, for the mid and high levels, the commercials may be skipped automatically or at the user""s discretion.
Instead of transmitting only one programming service in only one channel, the packetized program segments may be transported in a plurality of data streams. For example, program segments which provide jazz music may be provided in a first data stream, while program segments which provide classical music may be provided in a second data stream, and so forth. The term xe2x80x9cprogramming service streamxe2x80x9d is used herein to designate a data stream which carries data from a particular programming service. A programming service stream is analogous to a xe2x80x9cchannelxe2x80x9d of a conventional analog radio broadcast but need not be transmitted in a separate physical channel or spectrum.
Data can be provided which indicates access points for the program segments of the first and second programming service streams to allow a user to skip directly from a currently playing program segment on the first programming service stream to a starting point of a program segment in the second programming service stream. Thus, whenever the user changes data streams, the start of a segment may be played. This is in contrast to conventional radio systems, where the user generally misses the beginning of an audio selection being played when changing the channel, and cannot recover any portion of the selection that has already passed.
When the program segments include non-commercial segments and commercial segments, the non-commercial program segments can be transmitted as replacement programming in a replacement programming bandwidth of the transmitted data stream. The replacement program is gradually accumulated over time so that the premium subscriber can recover the replacement programming while the non-paying user recovers the commercial segments. The replacement programming replaces time which would have been occupied by the commercials. The total amount of programming for the users at each service tier can therefore be the same.
Corresponding apparatus are also presented.